import {getDecryptByBase64 as decrypt, getEncryptToBase64 as encrypt} from "./encryption"

const encodeReserveRE = /[!'()*]/g
const encodeReserveReplacer = c => '%' + c.charCodeAt(0).toString(16)
const commaRE = /%2C/g
const encode = str => encodeURIComponent(str)
  .replace(encodeReserveRE, encodeReserveReplacer)
  .replace(commaRE, ',')

const decode = decodeURIComponent

/**
 * 判断字符串是否是base64
 * @param { string } str
 * @returns { boolean }
 */
function isBase64(str) {
  if (str ==='' || str.trim() ===''){ return false; }
  try {
    return btoa(atob(str)) == str;
  } catch (err) {
    return false;
  }
}

/**
 * 序列化对象 并加密
 * @param {Object} obj
 */
export const stringifyQuery = obj => {

  const res = obj ? Object.keys(obj).map(key => {
    const val = obj[key]

    if (val === undefined) {
      return ''
    }

    if (val === null) {
      return encode(key)
    }

    if (Array.isArray(val)) {
      const result = []
      val.forEach(val2 => {
        if (val2 === undefined) {
          return
        }
        if (val2 === null) {
          result.push(encode(key))
        } else {
          result.push(encode(key) + '=' + encode(val2))
        }
      })
      return result.join('&')
    }

    return encode(key) + '=' + encode(val)
  }).filter(x => x.length > 0).join('&') : null

  return res ? `?${encrypt(res)}` : ''
}

/**
 * 解密  反序列化字符串参数
 * @param {String}} query
 */
export const parseQuery = query => {
  const res = {}

  query = query.trim().replace(/^(\?|#|&)/, '')

  if (!query) {
    return res
  }

  // 解密
  query = isBase64(query) ? decrypt(query) : query;

  query.split('&').forEach(param => {
    const parts = param.replace(/\+/g, ' ').split('=')
    const key = decode(parts.shift())
    const val = parts.length > 0
      ? decode(parts.join('='))
      : null

    if (res[key] === undefined) {
      res[key] = val
    } else if (Array.isArray(res[key])) {
      res[key].push(val)
    } else {
      res[key] = [res[key], val]
    }
  })
  return res
}
